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Ruthenium complexes containing Ph2PCH2CH2SPh as a mono- or bidentate ligand or both
Inorganica Chimica Acta, 62 (1982) 99-101
99
Ruthenium Complexes Containing Ligand or Both
Phz PCHz CH2SPh as a Mono- or Bidentate
ALAN R. SANGER* Alberta Research Council, 11315~87Avenue,
Edmonton,
Alta. T6G 2C2, Canada
and ROBERT W. DAY Department
of Chemistry, University of Victoria, Victoria, B.C. V8W 2Y2, Canada
Received March 4,1982
Reaction of [RuC~~(CO)~]~ with Ph2 PCH, CH2SPh (L) gives successively [RuC~,(CO)~(L)] and [RuCl, (CO),{ L)J , in each of which L is coordinated by the phosphorus atom alone. In contrast, the complexes [RuC13(L)], and [RuCl,(L)J each contain L as a bidentate ligand. The complex [RUG(CO)(L),] contains L as both a monodentate and a bidentate chelating ligand.
Introduction Reactions of equivalent or greater amounts of PhzPCH2 CH*SPh (L) [l] with Rh’ [2], Pdr* [3], or Pt” [3] give products containingL as either a monodentate (P) or bidentate (P, S) ligand. Herein we report the formation of a similar series of complexes of ruthenium(U) or ruthenium(M), and a novel complex containing both monodentate and bidentate L.
pyridine (L’) complex cis-[Ru(L’)Cl,(CO)Z] by the reaction of chlorine with [Ru(L’)(CO)~]~ [5]. In a separate experiment, a benzene solution of complex I and excess L was refluxed for 48 hours under an atmosphere of dinitrogen. After removal of solvent and subsequent attempted recrystallization of the product from dichloromethane/diethyl ether, impure [Ru(L), Cl,(CO),] , (3), was obtained in relatively poor yield as a white powder (v(C0) = 2056, 1993 cm-‘); (v(RuC1) = 301, 279 cm-l). This product is analogous to both [RuC12(C0)2(PPhs)2] [6] and [RuC12(CO),(L’),] [5]. The infra-red spectrum indicated that the pairs of carbonyl or chloroligands are each mutually cis. The 31P NMR spectrum (6(P) = +16.4 ppm vs. 85% HaP04) demonstrates that the phosphorus atoms are equivalent. Therefore the ligands L are mutually trans. It is interesting to note that complexes (2) and (3) each contain L as a monodentate (P) ligand. When equimolar quantities of [RuC13*3Hz0] and L react under an atmosphere of Nz the initial grey-
Results and Discussion
5’,;co
At room temperature in solution in dichloromethane the dinuclear complex [RuCl,(CO)3]2, (I), is cleaved by reaction with an equimolar or greater amount of L to form cis-[RuCIZ(CO)s(L)], (2), in which L is coordinated to ruthenium by only the phosphorus donor atom. This white, crystalline complex exhibits carbonyl bands in the IR spectrum (v(C0) = 2130(m), 2056(s), 1995(s) cm-‘; v(RuC1) = 307, 282 cm-‘) similar to those exhibited by cis[RuC1,(C0)3(PPh3)] [4], but the product is considerably more stable to loss of CO. This stability is all the more surprising considering the facile preparation of the chelated 2-diphenylphosphino-
Cl OC’
Ru’-
PPh,CH,CH2
S Ph
(2)
1 co
Cl
I ~hSCH$y~~phti-
,C’ PPh,CH,CH,Sph
(3)
co
(7
*Author to whom correspondence
0020-1693/82/0000-0000/$02.75
1
should be addressed.
0 Elsevier Sequoia/Printed
in Switzerland
100
green product is [RuCls(L)] , (4, v(RuC1) = 326(s,b) cm-‘), contaminated with other products from which it can be purified by extraction with CHsCls, addition of diethyl ether, and slow evaporation of the green solution. However, reaction of [RuC13*3HzO] with greater amounts of L gives more highly substituted complexes, with concomitant subsequent reduction of the central metal atom to ruthenium(H). When an ethanolic solution of [RuC1a*3Hz0] and excess L was refluxed for a prolonged time under an atmosphere of dinitrogen the pink product was [RuCl,(L),],, (5; v(RuC1) = 311(s) cm-‘). Each L is probably bidentate (P, S), thereby affording a 6-coordinate (18electron) complex. This product is of such low solubility in all solvents as to preclude determination of its molecular weight. When the above experiment was performed at lower temperatures, or for shorter periods, mixtures of products were obtained. The initial light-brown, precipitate formed when an ethanolic solution of [RuC1s*3HZO] reacts with CO and an equivalent or greater amount of L has a composition consistent with formulation as impure [RuaCl,(CO),(L)a] , (6) which would be analogous to [RuzC14(C0)2{Ph2P(CH2)4PPhz}3] [7]. The molecular weight of 6 also indicates that the product is a dinuclear complex which is partially dissociated in solution in CH2Br2 (M, 1298 calculated, 1566). When a similar reaction mixture is refluxed under an atmosphere of CO the product is instead the mononuclear complex [RuC12(CO)(L),], (7). Complex 7 is a non-electrolyte. The carbonyl band in the infra-red spectrum (Y(CO) = 1969 cm-‘; v(RuCl) = 308, 256 cm-‘) is of a value appropriate for a carbonyl ligand trans to a chloro-ligand [7]. The value of the coupling constant between the inequivalent phosphorus atoms (?i(P’) = 16.4 ppm; S(P2) = -13.9 ppm; 2J(P1-P2) = 349.1 Hz) shows that they are mutually trans [8]. The two ligands L are therefore dissimilar, one being monodentate (P) and the other bidentate (P, S). In contrast to related complexes of rhodium(I) [9], the chlorocomplexes herein described are not efficient catalysts for either the hydrogenation or hydroformylation of alkenes, having very low activity at moderate temperatures and atmospheric pressure. It is anticipated that hydrido-complexes derived from the above systems will be more active.
Experimental The ligand Ph2PCH2 CH2SPh was prepared as described in the literature [I] . Complexes [RuCls(CO)s]s and [RuC1s*xH20] (x N 3) were purchased from Strem Chemicals Inc., and were used without further purification. Solvents were dried, distilled, and flushed with the appropriate gas (CO or N2).
A. R. Sanger and R. W.Day
Infrared spectra of products were obtained from Nujol mulls using a Perkin-Elmer 283 instrument, and 31P NMR spect r a were obtained using a Bruker WPBO instrument. Elemental analyses were performed by Alfred Bernhardt Mikroanalytisches Laboratorium, Germany. The specific conditions for each reaction arre described in the text. Example 1 Under an atmosphere of Ns a mixture of [RuCls* 3H20] (0.065 g, 0.25 mmol) and Ph2PCH2CH2SPh (0.242 g, 0.75 mmol) in ethanol was successively refluxed for 52 hours, cooled to room temperature, filtered, and the precipitate dried under vacuum to yield, as a pink powder, [RuC12 (Ph2PCH2 CH2 SPh),], (Yield = 91%). Example 2 A mixture of [RuCls(CO)3]2 (0.061 g, 0.12 mmol) and Ph3PCH2CH2SPh (0.163 g, 0.51 mmol) in benzene (30 ml) was refluxed (2 h) under an atmosphere of N2 and then allowed to successively cool and evaporate to dryness. The sticky product was stirred with diethyl ether (1.5 h), and the mixture was filtered to give, as a pale, creamy-white powder, [RuCls (CO), (Ph, PCH2 CH, SPh)2 ] . The material was recrystallized from dichloromethane/diethyl ether (Yield -45%). Example 3 Under an atmosphere of CO a mixture of [RuCls* 3H20] (0.065 g, 0.25 mmol) and Ph2PCH2CH2SPh (0.242 g, 0.75 mmol) in ethanol (50 ml) was refluxed for 4 hours. The mixture was successively allowed to cool to room temperature, filtered, and the precipitate dried under vacuum to give, as a pale brown powder, [RuC12(CO)(Ph2 PCH2 CH2 SPh),] Slow evaporation of 25% of the mother liquor under a stream of CO gave a second crop of similar material (IR) as a fine off-white powder, (total yield -40%). Subsequent material precipitated by evaporation of the solvent was impure, and included unreacted starting material. When the mixture was refluxed under CO for much longer periods the major product was [RuC12(C0)2(Ph2PCH2CH2SPh)2], identified by comparison with the product of Example 2 above. Elemental Analyses of Products (calculated values in parentheses): (2): C, 47.51 (47.76); H, 3.42 (3.31); Cl, 12.05 (12.26); S, 5.57 (5.54)%. (3): C, 56.44 (57.79); H, 4.46 (4.39); Cl, 7.98 (8.12); P, 7.03 (7.10); s, 7.10 (7.35)%. (4): C, 45.48 (45.34); H, 3.76 (3.61); P, 5.98 (5.85); S, 6.15 (6.05)%
Ruthenium-Ph2PCH2CHzSPh
101
Complexes
(5): C, 58.73 (58.82); H, 4.78 (4.69); Cl, 8.28 (8.68); P, 7.40 (7.58); S, 7.54 (7.85)0/o. (6): Cl, 10.63 (10.37); P, 6.74 (6.80); S, 6.95 (7.03)% (C analyses were inconsistent). (7): C, 57.56 (58.29); H, 4.95 (4.53); Cl, 7.89 (8.39);P, 7.18 (7.33); S, 7.43 (7.59)0/o.
Acknowledgements This work was performed as part of the University of Victoria Chemistry Co-op Program (faculty advisor: F. P. Robinson). R. W. D. thanks Alberta Research Council for financial support.
References 1 D. L. DuBois, W. H. Byers and D. W. Meek, J. Chem. Sot. Dalton, 1011 (1975). 2 A. R. Sanger, C. G. Lobe and J. E. Weiner-Fedorak, Inorg. Chim. Acta Letters, 53, L123 (1981). 3 A. R. Sanger and C. G. Lobe, unpublished results. 4 B. F. G. Johnson, R. D. Johnston and J. Lewis, J. Chem. Sot. (A), 792 (1969). 5 M. M. Olmstead, A. Maisonnat, J. P. Farr and A. L. Balch, Inorg. Chem., 20, 4060 (1981). 6 M. S. Lupin and B. L. Shaw, J. Chem. Sot. (A), 741 (1968); B. R. James, L. D.Markham, B. C. Hui and G. L. Rempel, J. Chem. Sot. Dalton, 2241(1973); D. R. Fahev. J. Ora. Chem.. 38. 80 (1973). 7 M. Bressan-and P: Rigo, ho&. Chem., i4, 2286 (1975). 8 B. R. James, R.S. McMillan, R. H. Morris and D. K. W. Wang, Adv. Chem. Series, 167, 122 (1978).
9 X. Guo and A. R. Sanger, unpublished results.
99
Ruthenium Complexes Containing Ligand or Both
Phz PCHz CH2SPh as a Mono- or Bidentate
ALAN R. SANGER* Alberta Research Council, 11315~87Avenue,
Edmonton,
Alta. T6G 2C2, Canada
and ROBERT W. DAY Department
of Chemistry, University of Victoria, Victoria, B.C. V8W 2Y2, Canada
Received March 4,1982
Reaction of [RuC~~(CO)~]~ with Ph2 PCH, CH2SPh (L) gives successively [RuC~,(CO)~(L)] and [RuCl, (CO),{ L)J , in each of which L is coordinated by the phosphorus atom alone. In contrast, the complexes [RuC13(L)], and [RuCl,(L)J each contain L as a bidentate ligand. The complex [RUG(CO)(L),] contains L as both a monodentate and a bidentate chelating ligand.
Introduction Reactions of equivalent or greater amounts of PhzPCH2 CH*SPh (L) [l] with Rh’ [2], Pdr* [3], or Pt” [3] give products containingL as either a monodentate (P) or bidentate (P, S) ligand. Herein we report the formation of a similar series of complexes of ruthenium(U) or ruthenium(M), and a novel complex containing both monodentate and bidentate L.
pyridine (L’) complex cis-[Ru(L’)Cl,(CO)Z] by the reaction of chlorine with [Ru(L’)(CO)~]~ [5]. In a separate experiment, a benzene solution of complex I and excess L was refluxed for 48 hours under an atmosphere of dinitrogen. After removal of solvent and subsequent attempted recrystallization of the product from dichloromethane/diethyl ether, impure [Ru(L), Cl,(CO),] , (3), was obtained in relatively poor yield as a white powder (v(C0) = 2056, 1993 cm-‘); (v(RuC1) = 301, 279 cm-l). This product is analogous to both [RuC12(C0)2(PPhs)2] [6] and [RuC12(CO),(L’),] [5]. The infra-red spectrum indicated that the pairs of carbonyl or chloroligands are each mutually cis. The 31P NMR spectrum (6(P) = +16.4 ppm vs. 85% HaP04) demonstrates that the phosphorus atoms are equivalent. Therefore the ligands L are mutually trans. It is interesting to note that complexes (2) and (3) each contain L as a monodentate (P) ligand. When equimolar quantities of [RuC13*3Hz0] and L react under an atmosphere of Nz the initial grey-
Results and Discussion
5’,;co
At room temperature in solution in dichloromethane the dinuclear complex [RuCl,(CO)3]2, (I), is cleaved by reaction with an equimolar or greater amount of L to form cis-[RuCIZ(CO)s(L)], (2), in which L is coordinated to ruthenium by only the phosphorus donor atom. This white, crystalline complex exhibits carbonyl bands in the IR spectrum (v(C0) = 2130(m), 2056(s), 1995(s) cm-‘; v(RuC1) = 307, 282 cm-‘) similar to those exhibited by cis[RuC1,(C0)3(PPh3)] [4], but the product is considerably more stable to loss of CO. This stability is all the more surprising considering the facile preparation of the chelated 2-diphenylphosphino-
Cl OC’
Ru’-
PPh,CH,CH2
S Ph
(2)
1 co
Cl
I ~hSCH$y~~phti-
,C’ PPh,CH,CH,Sph
(3)
co
(7
*Author to whom correspondence
0020-1693/82/0000-0000/$02.75
1
should be addressed.
0 Elsevier Sequoia/Printed
in Switzerland
100
green product is [RuCls(L)] , (4, v(RuC1) = 326(s,b) cm-‘), contaminated with other products from which it can be purified by extraction with CHsCls, addition of diethyl ether, and slow evaporation of the green solution. However, reaction of [RuC13*3HzO] with greater amounts of L gives more highly substituted complexes, with concomitant subsequent reduction of the central metal atom to ruthenium(H). When an ethanolic solution of [RuC1a*3Hz0] and excess L was refluxed for a prolonged time under an atmosphere of dinitrogen the pink product was [RuCl,(L),],, (5; v(RuC1) = 311(s) cm-‘). Each L is probably bidentate (P, S), thereby affording a 6-coordinate (18electron) complex. This product is of such low solubility in all solvents as to preclude determination of its molecular weight. When the above experiment was performed at lower temperatures, or for shorter periods, mixtures of products were obtained. The initial light-brown, precipitate formed when an ethanolic solution of [RuC1s*3HZO] reacts with CO and an equivalent or greater amount of L has a composition consistent with formulation as impure [RuaCl,(CO),(L)a] , (6) which would be analogous to [RuzC14(C0)2{Ph2P(CH2)4PPhz}3] [7]. The molecular weight of 6 also indicates that the product is a dinuclear complex which is partially dissociated in solution in CH2Br2 (M, 1298 calculated, 1566). When a similar reaction mixture is refluxed under an atmosphere of CO the product is instead the mononuclear complex [RuC12(CO)(L),], (7). Complex 7 is a non-electrolyte. The carbonyl band in the infra-red spectrum (Y(CO) = 1969 cm-‘; v(RuCl) = 308, 256 cm-‘) is of a value appropriate for a carbonyl ligand trans to a chloro-ligand [7]. The value of the coupling constant between the inequivalent phosphorus atoms (?i(P’) = 16.4 ppm; S(P2) = -13.9 ppm; 2J(P1-P2) = 349.1 Hz) shows that they are mutually trans [8]. The two ligands L are therefore dissimilar, one being monodentate (P) and the other bidentate (P, S). In contrast to related complexes of rhodium(I) [9], the chlorocomplexes herein described are not efficient catalysts for either the hydrogenation or hydroformylation of alkenes, having very low activity at moderate temperatures and atmospheric pressure. It is anticipated that hydrido-complexes derived from the above systems will be more active.
Experimental The ligand Ph2PCH2 CH2SPh was prepared as described in the literature [I] . Complexes [RuCls(CO)s]s and [RuC1s*xH20] (x N 3) were purchased from Strem Chemicals Inc., and were used without further purification. Solvents were dried, distilled, and flushed with the appropriate gas (CO or N2).
A. R. Sanger and R. W.Day
Infrared spectra of products were obtained from Nujol mulls using a Perkin-Elmer 283 instrument, and 31P NMR spect r a were obtained using a Bruker WPBO instrument. Elemental analyses were performed by Alfred Bernhardt Mikroanalytisches Laboratorium, Germany. The specific conditions for each reaction arre described in the text. Example 1 Under an atmosphere of Ns a mixture of [RuCls* 3H20] (0.065 g, 0.25 mmol) and Ph2PCH2CH2SPh (0.242 g, 0.75 mmol) in ethanol was successively refluxed for 52 hours, cooled to room temperature, filtered, and the precipitate dried under vacuum to yield, as a pink powder, [RuC12 (Ph2PCH2 CH2 SPh),], (Yield = 91%). Example 2 A mixture of [RuCls(CO)3]2 (0.061 g, 0.12 mmol) and Ph3PCH2CH2SPh (0.163 g, 0.51 mmol) in benzene (30 ml) was refluxed (2 h) under an atmosphere of N2 and then allowed to successively cool and evaporate to dryness. The sticky product was stirred with diethyl ether (1.5 h), and the mixture was filtered to give, as a pale, creamy-white powder, [RuCls (CO), (Ph, PCH2 CH, SPh)2 ] . The material was recrystallized from dichloromethane/diethyl ether (Yield -45%). Example 3 Under an atmosphere of CO a mixture of [RuCls* 3H20] (0.065 g, 0.25 mmol) and Ph2PCH2CH2SPh (0.242 g, 0.75 mmol) in ethanol (50 ml) was refluxed for 4 hours. The mixture was successively allowed to cool to room temperature, filtered, and the precipitate dried under vacuum to give, as a pale brown powder, [RuC12(CO)(Ph2 PCH2 CH2 SPh),] Slow evaporation of 25% of the mother liquor under a stream of CO gave a second crop of similar material (IR) as a fine off-white powder, (total yield -40%). Subsequent material precipitated by evaporation of the solvent was impure, and included unreacted starting material. When the mixture was refluxed under CO for much longer periods the major product was [RuC12(C0)2(Ph2PCH2CH2SPh)2], identified by comparison with the product of Example 2 above. Elemental Analyses of Products (calculated values in parentheses): (2): C, 47.51 (47.76); H, 3.42 (3.31); Cl, 12.05 (12.26); S, 5.57 (5.54)%. (3): C, 56.44 (57.79); H, 4.46 (4.39); Cl, 7.98 (8.12); P, 7.03 (7.10); s, 7.10 (7.35)%. (4): C, 45.48 (45.34); H, 3.76 (3.61); P, 5.98 (5.85); S, 6.15 (6.05)%
Ruthenium-Ph2PCH2CHzSPh
101
Complexes
(5): C, 58.73 (58.82); H, 4.78 (4.69); Cl, 8.28 (8.68); P, 7.40 (7.58); S, 7.54 (7.85)0/o. (6): Cl, 10.63 (10.37); P, 6.74 (6.80); S, 6.95 (7.03)% (C analyses were inconsistent). (7): C, 57.56 (58.29); H, 4.95 (4.53); Cl, 7.89 (8.39);P, 7.18 (7.33); S, 7.43 (7.59)0/o.
Acknowledgements This work was performed as part of the University of Victoria Chemistry Co-op Program (faculty advisor: F. P. Robinson). R. W. D. thanks Alberta Research Council for financial support.
References 1 D. L. DuBois, W. H. Byers and D. W. Meek, J. Chem. Sot. Dalton, 1011 (1975). 2 A. R. Sanger, C. G. Lobe and J. E. Weiner-Fedorak, Inorg. Chim. Acta Letters, 53, L123 (1981). 3 A. R. Sanger and C. G. Lobe, unpublished results. 4 B. F. G. Johnson, R. D. Johnston and J. Lewis, J. Chem. Sot. (A), 792 (1969). 5 M. M. Olmstead, A. Maisonnat, J. P. Farr and A. L. Balch, Inorg. Chem., 20, 4060 (1981). 6 M. S. Lupin and B. L. Shaw, J. Chem. Sot. (A), 741 (1968); B. R. James, L. D.Markham, B. C. Hui and G. L. Rempel, J. Chem. Sot. Dalton, 2241(1973); D. R. Fahev. J. Ora. Chem.. 38. 80 (1973). 7 M. Bressan-and P: Rigo, ho&. Chem., i4, 2286 (1975). 8 B. R. James, R.S. McMillan, R. H. Morris and D. K. W. Wang, Adv. Chem. Series, 167, 122 (1978).
9 X. Guo and A. R. Sanger, unpublished results.